Recuperator



Sept. 5, 1933. G. W. BATCHELL RECUPERATOR Filed May 29, 1931 3Sheets-Sheet 1 Sept. 5, 1933- s. w. BATCHELL 1,925,711

RECUPERATOR Filed May 29, 1931 3 Sheets-Sheet 2 44 fig-4 9mm Sept. 5,1933. 5, w BATCHELL 1,925,711

RECUPEBATOR Filed May 29, 1951 :5 Sheets-Sheet 5 Patented Sept; 5%, 1933FATE cries RECUPERATOR George W. Batch'ell, Toledo, Ohio, assignor toFrangeo Company, Toledo, Ohio, a corporation of Ohio Application May 29,1931. Serial No. 540,914

7 Claims. (Cl. 263-) This invention relates to recuperator constructions for furnaces. It particularly relates to a recuperatorconstruction for the pre-heating of gases preparatory to their ignitionwithin the 5 firing chamber of the furnace. Theinvention provides ameans for conveying exhaust gases from, the firing chamber of thefurnace through units interspersed'in the chamber through which freshgases are directed towards the firing cham- 0 her to heat the freshgases preparatory to ignition. The invention also provides units whichare heat insulated to prevent the rapid transmission of heat from theexhaust gases, as they are first received from. the firing chamber, tothe 15 exterior of the units and thereby provides a means formaintaining the exhaust gases in all the units at a high degree of heatwhich gradually diminishes as the exhaust gases near the outlet of theunits, effecting thereby a rapid raising of th temperature in a largevolume of fresh gas as it is moved through a relatively small chambertoward the firing chamber of the furnace. The invention also providesmeans for sealing the units from the chamber in which the fresh gasesare moved toprevent the mixing of the exhaust gases with the fresh gasesand therebypermits of the use of a pressure means to move the gasesthrough the units or the chambers.

The invention further provides a means for preventing explosions fromtaking place by reason of mixing the heated exhaust gases with the freshgases whereby spontaneous ignition and combustion might occur. i H

Another object of my invention is to provide means for protecting thesealing parts about the units fromdeterioration or transfiguration bythe extreme temperatures of the exhaust gases.

A further object of my invention is to provide units for preheatinggases which aresupported on fitted blocks and which may easily beremoved for adjustment or replacement of the units.

The invention consistsinother features and advantages which will appearfrom the following description and upon examination of the drawings.Structures containing the invention may partake of different forms andmay be varied in their details and still embody the invention. Toillustrate a practical application of the invention r I have selected arecuperator embodying the invention as an example of the variousstructures and details thereof that contain the invention and shalldescribe it hereinafter, it being understood that variations may be usedwithouta corresponding use of other features and without de- 5 partingfrom the spirit of the invention. The

particular structure selected is shown inthe accompanying drawings.

Fig. 1 of the accompanying drawings illustrates a view of across-section of the recuperator construction. Fig. 2 illustrates a Viewof a section taken on the plane of the line 22 indicated in Fig. 1.Fig.3 illustrates a View of a section taken on theplane of the line 3-3indicated in Fig. 1. Fig. 4 illustrates a cross-sectional'view of one ofthe heating units of the recuperator. Fig. 5 illustrates an enlargedview of a portion of the units. Fig. 6 illustrates a perspective View ofone of the supporting blocks for the heating 'units. Fig. '7 illustratesa crosssection of a modified form of the heating units.

The recuperator illustrated in the accompanying drawings is particularlyprovided for furnaces in which it is desirable and necessary to maintainhigh temperatures, such as a glass furnace, and consequently in whichlarge quantities of fuel gases and vapors are burned to maintain suchtemperatures. It has been found, as is well known, that to heat thegases preparatory to their ignition results in a more efficient andcomplete oxidation of the gases and the obtaining of higher calorificvalues in such oxidation. Therefore, to so treat the gases bypresheating, the cost of maintaining high temperature, and consequentoperation of the furnace, will be reduced. I-Ieretofore, regeneratorconstructions have been provided in which the gases are pro-heated bybeing passed through a chamber containing checkerwork which has beenpreviously heated by passing hot exhaust gases through the chamber andin contact with the checkerwork. Such chambers have been, and are,commonly built below the ground surface level andrequire large space andexpenditure of money to install. They have proven not only cumbersome,but inefficient in raising the temperature of the fuel gases previous toignition and require alternate operation of heating and cooling. Underthe present day circumstances of rapid'and steady operation, the fuelgases cannot be permitted to remain a sufficient length of'tirne withinthe chamber of the well known regenerator to raise the temperatures ofgases to an efficient degree. Therefore, I have provided a plurality ofunits through which exhaust gases are conducted and located within achamber through which fresh gases are. conducted to the burner. Thefresh gases in moving through the chamber take up the heat of theexhaust'gases by transmission through the walls of the units. The unitsmay be formed of refractory materials, such as fired clay, to preventero- 110 sion by the high temperature and volatile material of theexhaust gases. The units may be surrounded by suitable metal jackets orshells which seal the units and prevent the escape of exhaust gasesthrough the clay parts which may become cracked by reason of the heatdistortion. Thus, the hot exhaust gases may be directed from the firingportion of the furnace through a plurality of such units to heat thefresh gases moving through the air chamber in contact with the units.

In order to retard the transmission of heat an to protect the shells orjackets from melting and fusion, by reason of the heat, the clay partsof the units may be corrugated so that contact with the metal jackets orshells is reduced to a small area and the jackets suitably held inspaced relation to the clay parts, thereby forming a plurality ofinsulating chambers between the clay partsand the jacket in which may belocated a low conductant of heat, such as air. Consequently, there willbe a reduced temperature gradient between the various units as theexhaust gases progress from one unit to another and a consequent hightemperature gradient between the fresh gases as they are introduced intothe air chamber and delivered to the burner and the firing chamber ofthe furnace. This feature permits the use of a small heating chamber forfresh gases and rapid utilization of such fresh gases in operation ofthe furnace.

The recuperator shown for purposes of illustration is supported on asuitable floor 4 and has walls 5 which are covered by a roof 6 to form arecuperator chamber '7. The chamber 7 is connected preferably to amixing chamber of a fur nace by such a passage-way as the passage-way10. A gas, such as air, may be introduced into the chamber '7 through avent 11 located in the lower part of the wall 5. The vent 11 ispreferably controlled by a damper 12. The air may be moved through thechamber '7 to the passageway leading to the mixing chamber of a furnace.

In order to heat the air as it moves through the chamber '7 to raise thetemperature preparatory to the introduction of the air to the burner ofa furnace, a plurality of heat exchange units may units.

be located throughout the chamber 7. The units 20 are preferably tubularin shape and are formed of refractory material, such as fire clay. Theunits 20 are supported by Y-shaped blocks 21 which are adapted to fitabout the units 20 and form walls 22. The blocks 21 not only support theunits 20, but also space them in staggered relationship to each other inorder to baffie the movement of air through the chamber 7 about theunits. The units 20 are provided with flanges 24 which may be formedintegrally with the units and are adapted to extend over the blocks 21,engaging the blocks and substantially sealing the points of connectionbetween the blocks and the Suitable I beams 23 are supported in thewalls 5 and cooperate with the walls 22 of blocks 21 to support theunits 20 within the chamber 7.

The walls 22 formed of blocks 21, divide the chamber 7 into a series ofseparate compartments 25, 26 and 27. The exhaust gases are collected anddirected from the firing portion of a furnace and are introduced intothe compartmerit 27 by a passage-way 30. A baffie 31 may be located inthe compartment 27 which sub-divides the compartment and directs theexhaust gases from the compartment 27 through the units 20 connectingthe compartment 27 to the compartment 25. The compartment 25 may also beprovided with a bafile 32 which directs the exhaust gases through otherof the units 29 back to the compartment 27. A suitable conduit 33 ispreferably connected to lower portions of the compartment 25 below thebafiie 32 to draw the exhaust gases back through still other of theunits 20 and out through the conduit 33. Thus, the exhaust gases will bedrawn through successive groups of units 20 to heat the units 20 and theair which may be moved through the compartment 26.- As the gasesprogress from the uppermost units to the lower-most units, thetemperature of the exhaust gases will gradually decrease as the heat istransmitted to the air in the compartment 26.

In order to prevent the air which may be moved in the compartment 26from becoming mixed with the exhaust gases which may escape throughcracks or lesions formed in the units 20 caused by heat distortion, theunits 20 are surrounded by metal jackets do, The jackets 49 may beformed of chromium alloy steel or any suitable metal having high heatresistant qualities. The units 20 may have corrugated surfaces 41 formedas by fluting the exterior surface of the units, as shown at 42 in Fig.l, or may have, as in the modified form shown in 7, a continuous sinuouscorrugated surface l3.

The surfaces 41 or 43 are located in contact with, and hold the jacketsl0 in spaced relationship with the units 2e and form a plurality ofchambers 44 about the units 20 and between the jackets 4i) and theunits. The chambers 44 may be filled with a substantial. non-conductant,such as air. Thus, the exterior surfaces of the jackets will besubstantially heat insulated from the units 20 and will transmit to theair moving through the compartment 26 only such heat as is conveyedthrough the small areas of the parts of the corrugated surface of theunits that'contact with the jackets, and the lesser transmission of heatbyradiation from the fire clay to the metal tubes that is conductedthrough the air in the corrugations or the chambers between the ridgesof the fluted tube. As the exhaust gases move through successive groupsof units 20 the heat will be gradually transmitted to the air within thecompartment 26.

In order to seal the ends of the jackets 40 and to provide an interiormetallic veneer or covering to the walls 22 of the blocks 21 to preventmixture of the exhaust gases and the air, the jackets 40 may be securedas by welding in openings 46 formed in channel plates 43. The channelplates 48 preferably extend the length of the recuperator chamber 7 andcoact with one another to support the ends of the jackets 40 in positionwithin the compartment 26 and 1 seal the walls 22.

Thus, the exhaust gases will be conveyed from the furnace to the stackthrough passage-ways and chambers having refractory walls highlyresistant to the 'heat of the exhaust gases andthe fresh gases will beconveyed through chambers having sealed metallic veneer wallssubstantially heat insulated from the exhaust gases to the firingportions of the furnace.

The recuperator may be easily disassembled by removing the blocks andchannel plates 48 for repair or adjustment of the parts within therecuperator. The parts may be reassembled by replacing the parts as theywere removed for disassembiy.

I claim:

1. In a recuperator heat exchange unit, a tubular clay body havingcorrugated exterior surfaces, a metallic jacket located about the claybody, means for directing heated gases through the clay body, and meansintermediate the clay body and the metallic jacket resistant to thetransmission of heat of the gases from the clay body to the exteriorsurface of the jacket.

2. In a recuperator, a'chamber, a plurality of refractory bodies havingmetallic jackets, a plurality of Y-shaped blocks forming walls forsupporting the refractory bodies in staggered relationship within thechamber, a plurality of channel plates having openings to receive themetallic jackets and adapted to seal the walls.

3. In a recuperator, a chamber having an inlet and an outlet, the outletconnected to a furnace, the inlet having a damper for controlling theinlet, a plurality of hollow refractory bodies located in the chamber, aplurality of metal jackets located about the refractory bodies, aplurality of Y-shaped blocks forming walls for supporting the claybodies in staggered relationship in the chamber, a plurality of channelplates 00- acting to form a veneer Wall contiguous to the block Wall,the channel plates having openings for supporting the metal jackets,means for directing exhaust gases from the furnace through therefractory bodies to heat the gas within the chamber for causingmovement of the gas toward the furnace.

4. In a recuperator, a passageway, a chamber connected to thepassageway, a plurality of heat exchange units extending through thechamber,

each of the heat exchange units comprising a pair of concentric tubes,one of the tubes located within the other and having longitudinalperipheral ridges for engaging the other tube and forming a plurality ofsubstantially sealed chambers located about the said inner tube forresisting heat transmission from the interior of the heat exchange unitsto the first named chamber.

5. In a recuperator for a furnace, the recuperator having an inlet andan outlet, a plurality of intercommunicating tubular heat exchange unitslocated between the inlet and the outlet, means for directing hotexhaust gases from the furnace through the heat exchange units'proximate to the outlet and progressively therefrom to the unitsproximate to the inlet, the heat exchange units having means forresisting the transmission of heat whereby the heat transmitted by theheat exchange units proximate to the outlet will be substantially of thesame degree as that transmitted by the heat exchange units at the inlet.

6. Ina recuperator for a furnace, the recuperator having an inlet and anoutlet, a plurality of intercommunicating heat exchange units locatedbetween the inlet and the outlet, means for directing hot exhaust gasesfrom the furnace through the heat exchange units, each of the heatexchange, units comprising a pair of concentric tubes, one of the tubeslocated within the other and having longitudinal peripheral ridges forengaging the other tube, and forming a plurality of sealed chambersbetween the tubes resistant to the transmission of heat whereby the heattransmitted by all the heat exchange units will be substantially of thesame equal degree in any of the units between the inlet and the outlet7. In a recuperator for a furnace, a passageway for directing fuel gasto the furnace, a chamber connected to the passageway, a heat exchangeunit located in the chamber comprising a tubular clay body havingcorrugated exterior GEORGE W. BATCHELL.

